Add architecture for simulating memory pressure notifications in all processes

content/browser/memory/memory_pressure_controller.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_MEMORY_MEMORY_PRESSURE_CONTROLLER_H_
 #define CONTENT_BROWSER_MEMORY_MEMORY_PRESSURE_CONTROLLER_H_
 
 #include <set>
 
 #include "base/callback.h"
+#include "base/memory/memory_pressure_listener.h"
 #include "base/memory/singleton.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 class MemoryMessageFilter;
 
 class CONTENT_EXPORT MemoryPressureController {
  public:
   // These methods must be called on the IO thread.
   void OnMemoryMessageFilterAdded(MemoryMessageFilter* filter);
   void OnMemoryMessageFilterRemoved(MemoryMessageFilter* filter);
 
-  // This method can be called from any thread.
+  // These methods can be called from any thread.
   void SetPressureNotificationsSuppressedInAllProcesses(bool suppressed);
+  void SimulatePressureNotificationInAllProcesses(
+      base::MemoryPressureListener::MemoryPressureLevel level);
 
   // This method can be called from any thread.
   static MemoryPressureController* GetInstance();
 
  protected:
   virtual ~MemoryPressureController();
 
  private:
   friend struct base::DefaultSingletonTraits<MemoryPressureController>;
 
   MemoryPressureController();
 
   // Set of all memory message filters in the browser process. Always accessed
   // on the IO thread.
   typedef std::set<scoped_refptr<MemoryMessageFilter>> MemoryMessageFilterSet;
   MemoryMessageFilterSet memory_message_filters_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryPressureController);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEMORY_MEMORY_PRESSURE_CONTROLLER_H_